Toy example of purescript argonaut generic encoding

Main.purs

module Main where
  
import Control.Monad.Eff (Eff)
import Control.Monad.Eff.Console (log, CONSOLE)
import Data.Argonaut.Core (Json, stringify)
import Data.Argonaut.Generic.Aeson (encodeJson)
import Data.Generic 
import Data.Maybe (Maybe(..))
import Prelude (($), Unit)

newtype EmailAddress = EmailAddress String
derive instance genericEmailAddress ∷ Generic EmailAddress
  
newtype Email = Email{
  to ∷ EmailAddress
, from ∷ EmailAddress
, subject ∷ Maybe String
, content ∷ Maybe String
}
derive instance genericEmail ∷ Generic Email


newtype BatchEmails = BatchEmails{
  emails :: Array Email
}
derive instance batchBatchEmails ∷ Generic BatchEmails


aBatchOfEmails :: BatchEmails
aBatchOfEmails = BatchEmails{
  emails : [ 
     Email{
      to : EmailAddress "[email protected]"
    , from: EmailAddress "[email protected]"
    , subject: Nothing
    , content : Just "Hello, World!"
    }
   , Email{
      to : EmailAddress "[email protected]"
    , from: EmailAddress "[email protected]"
    , subject: Just "This is a subject"
    , content : Nothing
  }
  ]
}

anEncodedBatchOfEmails :: Json
anEncodedBatchOfEmails = encodeJson aBatchOfEmails


main :: ∀ eff . Eff (console ∷ CONSOLE | eff) Unit
main = log $ stringify anEncodedBatchOfEmails